International Journal Of Global Innovations -Vol.1, Issue.II Paper Id: SP-V1-I2-224 ISSN Online:

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1 DESIGN AND THERMAL ANALYSIS OF CAM SHAFT IN AUTOMOBILES #1 Linga Murthy Pydi - M.Tech Pursuing, #2 MD.Ezaz Khan-Asst.Professor, Department of Mechanical Engineering, MOTHER THERESSA COLLEGE OF ENGINEERING & TECHNOLOGY, Peddapalli, Karimnagar, TS, India. Abstract: Camshaft can be defined as a machine element having the curve outlined or a curved grooved, gives the predetermined specified motion to another element called the follower. In automotive field, Camshaft and its follower take importance roles to run the engine. Nowadays the car maker have developed the vary schemes of cam profile to match with the engine performance. Since the system deals with high load and high speed and many analyses have been carried out on the failure of the components. The analysis is done either by experimental or finite element analysis. The result from the finite element analysis is an approximate of the component failure. In the meantime, the software development is improving in this few decades. Keywords: fatigue fracture, camshaft, lobes, Single Overhead Cam (SOHC), Double Overhead Cam (DOHC). I.INTRODUCTION Camshaft is one of the key parts or components in the engines of automobile and other vehicles. The performance is to control the open and close intervals of the inlet and exhaust poppet valves by its cams. Due to the cyclic impact loading on the contacting surfaces of the cam and the follower, it often gives rise to premature wear of cam profile and affects a routine run of the valve gear such as the rotational speed, valve displacement and the torque. CAMSHAFT On the other hand, simultaneously the most serious, under cyclic bending and torsion, fatigue fracture of camshaft initiating at stress concentration easily occurs. Therefore it demands the camshaft has not only excellent wear resistance but also adequate anti-impact toughness. The camshaft is undoubtedly the most important single component to be selected when tuning the four-stroke engine. The correct choice is often difficult to make and this chapter is principally concerned in setting out the problems and facts, in order that the correct decision can be made for an individual application. Recognition of the profile. The cam lobe is made up of four essential elements The base circle or clearance circle, often called the heel, together with the ramp - the flank - and the nose. The BASE CIRCLE is the area of the cam in which little or no contact takes place with the cam follower. The centre of the base circle duration lies at approximately 180 degrees from the nose centre line and is the point at which valve clearances are normally set. The RAMP is the area joining the base Paper ijgis.com OCTOBER/2014 Page 10

2 circle to flank, and is designed to take up valve clearance in a controlled manner, immediately prior to the start of valve lift. II.RELATED WORK The FLANK lifts the valve train with the spring in compression and accelerates to its maximum speed. The NOSE takes over at this point and controls the valve train deceleration until it momentarily comes to rest at full lift, when the process reverses itself to the lower valve back to its seat, where the ramp will re-open the clearance. This design feature means that individual cam lobes and tappets bed together after an initial running period, and should therefore never be allowed to re-mate with other components during later reassembly procedures. Camshafts are made from either cast-iron or steel with the latter usually recognisable by their smooth forged or turned finish between the lobes as opposed to the rougher finish of the former which are left as cast in this area. In some cases they are also turned between the lobes to reduce the core size, usually done when an increase in lift dictates a smaller base circle diameter. Cast iron shafts made of proferal or K iron, have the lobes and gears heat treated by flame or induction hardening processes, whereas chill cast components are hardened in the vital areas during the casting process.whatever production method is used, cast-iron cam lobes finish up with a hardness pattern as in that is, about a quarter of an inch depth of hardness over the nose, tapering in depth down each flank. The whole procedure exerts an enormous strain on the components involved, sometimes stacking-up contact stresses over the cam nose as high as 1300 Meganewtons/sq.m. (200 lbs/sq.in.), calling for a high degree of accuracy in design and manufacture, together with the need for great care and attention when fitting. The cam nose stress stack-up is the result of a number of unavoidable design constrictions. No matter how tight the engine manufacturing tolerances, there will always be a small amount of mis-alignment or out-of-square mating between components, sometimes causing hairline or pressure point contact. (Fig. 80) In order to minimise the effects of this possibility, cam lobes are often purposely machined with a taper to mate with a spherically ground tappet face creating an intentional but calculable high pressure footprint, slightly offset from the tappet centre-line to promote rotation of the tappet, thus improving overall service life. This means that the base circle is usually relatively soft, which is acceptable because there is little or no load at this point. Because of this hardness pattern, these cams are particularly suitable for regrinding; only requiring final refinishing with a black, oil retaining, phosphate coating. Steel cams, on the other hand, are case hardened, which means that they finish up with a thin hardened layer, usually about 1.0mm thick, which is penetrated when the cam is reground. This necessitates heat treatment or hard facing to regain acceptable hardness after a regrind. Lobe hardness over the nose should be Rockwell C on cast iron and Rockwell C on steel. Paper ijgis.com OCTOBER/2014 Page 11

This is clearly illustrated in which shows a selection of racing cam shapes from a variety of engines. A is a standard Fiat, B is a racing XK140 Jaguar, C is a racing Hillman Imp.

3 This is clearly illustrated in which shows a selection of racing cam shapes from a variety of engines. A is a standard Fiat, B is a racing XK140 Jaguar, C is a racing Hillman Imp. D, which most experts would define as a very mild cam, was the profile used in the contemporary Golf 1.8 GTI racing engines. E is a standard Triumph Bonneville, F is a standard Ford 2.0 OHC, G is a racing Honda. The shape of the lobe is entirely dependent on the design of the components that work with it and will vary hugely from engine to engine. The technical requirements of successful high performance cam design require attention to a number of simple but vital engine component functions. The vast majority of production engines have valve train mechanisms that generate symmetrical motion at the valve. This is achieved by either directly moving the valve with conventional direct operating cam technique in which case a symmetrical cam profile imparts a symmetrical valve motion, or by moving the valve via a rocker mechanism, which imparts symmetrical valve motion by compensating for the constantly varying rocker ratio by using an asymmetrical cam profile. However, modern computer design and analysis techniques allow for the development of cams that impart asymmetrical motion to the valve, thus taking advantage of part of the generous safety margins that are built into standard engine valve train dynamics. III. DESIGN OF SHAFT A shaft is a rotating member usually of circular cross section (solid or hollow), which is used to transmit power and otational motion. Axles are non rotating member. Elements such as gears, pulleys (sheaves), flywheels,clutches, and sprockets are mounted on the shaft and are used to transmit power from the driving device (motor or engine) through a machine. The rotational force (torque) is transmitted to these elements on the shaft by press fit, keys, dowel, pins and splines. The shaft rotates on rolling contact or bush bearings. Various types of retaining rings, thrust bearings, grooves and steps in the shaft are used to take up axial loads and locate the rotating elements. Paper ijgis.com OCTOBER/2014 Page 12

Splines in hubs and shafts allow axial motion and transmits torque The most frequently encountered stress situation for a rotating shaft is to have completely reversed bending and All keys, pins and

4 Splines in hubs and shafts allow axial motion and transmits torque The most frequently encountered stress situation for a rotating shaft is to have completely reversed bending and All keys, pins and splines give rise to stress concentration in the hub and shaft Loads on shaft:shaft loaded in only torsion: torsion may have a steady (Tav) and a cyclic (Tr) component. Design of shaft Axial dimensions are often fixed from the layout of the mechanism. Design recommendation is to keep the axial lengths as short as possible to limit bending stress. Simply supported shaft is better than cantilever or overhang shaft. Shaft design is to determine the diameter of the shaft such that it withstand the applied loads, after stress concentrations, with a known factor of safety. steady torsional stress. In other situations, a shaft may have a reversed torsional stress along with reversed bending stress. From Soderberg s fatigue criterion, the equivalent static bending and torsional stresses are: Using these equivalent static stresses in our static design equation, the equation for rotating shaft is: IV. EXPERIMENTAL RESULTS Design of rotating shafts and fatigue consideration The most generalized situation the rotating shaft may have both steady and cyclic components of bending stress (sav,sr) and torsional stress (tav,tr). Paper ijgis.com OCTOBER/2014 Page 13

Unit System Angle Rotational Velocity Temperature Metric (mm, kg, N, s, mv, ma) Degrees rad/s Celsius Degrees rad/s Celsius Model (A4) > Static Structural (A5) > Solution (A6) > Normal Elastic Strain

5 Unit System Angle Rotational Velocity Temperature Metric (mm, kg, N, s, mv, ma) Degrees rad/s Celsius Degrees rad/s Celsius Model (A4) > Static Structural (A5) > Solution (A6) > Normal Elastic Strain > Figure Model (A4) > Static Structural (A5) > Force Model (A4) > Static Structural (A5) > Solution (A6) > Equivalent Stress > Figure Model (A4) > Static Structural (A5) > Solution (A6) > Total Deformation > Figure Paper ijgis.com OCTOBER/2014 Page 14

6 V. CONCLUSIONS Cam profile design and cam design for manufacture is a specialist topic. With the advent of mathematically complex but accurate, user-friendly and highly visual computer software, as with valve lift profile design can be professionally executed by the engineer who normally designs the power producing cylinder-head components of the engine. However excellent those design techniques may be for cam design and manufacture, the quality of the ensuing cam profile design and its subsequent behavior within an engine is only as good as that of the valve lift profile design, and the quality of its inherent smoothing techniques, which precede it. Design and analysis of cam shaft is done by using CATIA and ANSYS, as these designs can be modified according to the results taken from analysis software. REFERENCES: [1] Handbook of Die Design by Ivana Suchy [2] Machine Design by R.S. Khurmi and J.K. Gupta, Eurasia Publishing House (P) Ltd., New Delhi [3] Pro/Engineer WildFire 2.0 by Steven G. Smith [4] Product Design and Manufacturing by R.C. Gupta and A.K. Chaitle [5] Theory of Machines by P.L. Ballney, Khanna Publishing, New Delhi. [6] Theory of Machines by R.S. Khurmi and J.K. Gupta, S.Chand & Co., New Delhi. [7] Theory of Machines by S.S. Rattan, Tata McGraw Hill, New Delhi. [8] 4stHEAD design software, Prof. Blair and Associates, Belfast,Northern Irelandn (see [9] G.P. Blair, C.D. McCartan, H. Hermann, The Right Lift, Race Engine Technology, issue 009, July 2005 ISSN (see and also [10] F.Y. Chen, Mechanics and Design of Cam Mechanisms, Pergamon Press, July 1,1982, ISBN [11] R.L. Norton, Cam Design and Manufacturing Handbook, Industrial Press Inc., ISBN [12] D. Dowson, G.R. Higginson, Elasto-Hydrodynamic Lubrication, Ed.2 in SI units, Oxford University Press & Pergamon Press, 1977, ISBN Paper ijgis.com OCTOBER/2014 Page 15

Keywords: Von Mises, Piston, Thermal Analysis, Pressure, CATIAV5R20, ANSYS14 I. INTRODUCTION

Keywords: Von Mises, Piston, Thermal Analysis, Pressure, CATIAV5R20, ANSYS14 I. INTRODUCTION Finite Element Analysis of IC Engine Piston Using Thermo Mechanical Approach 1 S.Sathishkumar, Dr.M.Kannan and 3 V.Raguraman, 1 PG Scholar, Professor, 3 Assistant professor, 1,,3 Department of Mechanical